<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8" />
  <title>图片二维码识别</title>
  <!-- <script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script> -->
  <!-- <script src="https://cozmo.github.io/jsQR/jsQR.js"></script> -->
  <script src="../../Library/jquery-3.5.1.min.js"></script>
  <script src="./jsQR.min.js"></script>
</head>

<body>
  <span lan_id="bc">选择图片</span> <input type="file" id="pictureChange" />
  <div>
    <h2>识别结果：</h2>
    <ul id="result">
    </ul>
  </div>
</body>
<script type="text/javascript">
  $("body").append('<canvas id="qrcanvas" style="display:none;"></canvas>')
  $("#pictureChange").change(function (e) {
    var file = e.target.files[0];
    if (window.FileReader) {
      var fr = new FileReader();
      fr.readAsDataURL(file);
      fr.onloadend = function (e) {
        var base64Data = e.target.result;
        base64ToqR(base64Data)
      }
    }
  })

  function base64ToqR(data) {
    var c = document.getElementById("qrcanvas");
    var ctx = c.getContext("2d");

    var img = new Image();
    img.src = data;
    img.onload = function () {
      $("#qrcanvas").attr("width", img.width)
      $("#qrcanvas").attr("height", img.height)
      ctx.drawImage(img, 0, 0, img.width, img.height);
      var imageData = ctx.getImageData(0, 0, img.width, img.height);
      const code = jsQR(imageData.data, imageData.width, imageData.height, {
        inversionAttempts: "dontInvert",
      });
      if (code) {
        showCode(code.data)
      } else {
        alert("识别错误")
      }
    };
  }

  function showCode(code) {
    $("#result").append("<li>" + code + "</li>")
  }
</script>

</html>